Flexible plate saddle lock-up system

ABSTRACT

The invention is a system utilizing cylindrically shaped saddles for mounting flexible printing plates. The leading edges of said saddles are designed to securely grip one end of a printing plate with a cam biased clamping bar. The trailing edge of said saddles include a slotted member to retain the other end of said printing plate, said slotted member being spring biased to tension said printing plate. A separate tool which interacts between the leading edge of one saddle and the trailing edge of another saddle when both saddles are mounted on press is utilized to override the spring biasing of the slotted member.

[54] FLEXIBLE PLATE SADDLE LOCK-UP SYSTEM [75] Inventor: Richard L. Moyer, Newark, Del.

{73] Assignee: Hercules Incorporated, Wilmington,

Del.

22 Filed: Feb. 27, 1973 21 App1.No.:336,320

[52] US. Cl. 101/415.1 [51] Int. Cl B411 27/12 [58] Field of Search l0l/4l5.1, 378

[56] References Cited UNITED STATES PATENTS 1,674,426 6/1928 Durrant 101/378 1,954,550 4/1934 Weide l0l/4l5.l X 1,966,121 7/1934 2,050,950 8/1936 103,617 12/1937 Gericke ..101/415.1 2211910 8/1940 Read ..10l/4l5.l 2 748,699 6/1956 Bobst 101/378 2 768,578 10/1956 Park et al. l0l/415.l 2,990,000 6/1961 Mangus et a1. 10l/4l5.1 X 3,017,830 1/1962 Penner 10l/4l5.1 3,110,255 11/1963 Jeschke et a1. 10l/4l5.l 3,195,458 7/1965 Nystrand l01/415.1 3,335,663 8/1967 Harenza 101/415.1

1451 Jan. 7, 1975 3,416,447 12/1968 Pozniak 10l/415.1 3,424,085 1/1969 Beisel 101/415.1 3,470,817 10/1969 Heimlicher et a1. 101/378 3,696,744 10/1972 Etchell l0l/415.1

3,750,572 8/1973 Etchell l01/415.l 3,791,295 9/1972 Albright 101/415.1

FOREIGN PATENTS OR APPLICATIONS 855,408 7/1949 Germany 10l/4l5.1

1,184,855 7/1968 Great Britain 1()l/4l5.1

Primary IixaminerRobert E. Pulfrey Assistant E.raminerPaul J. Hirsch Attorney, Agent, or Firm.lames W. Peterson [57] ABSTRACT The invention is a system utilizing cylindrically shaped saddles for mounting flexible printing plates. The lead 1 Claim, 8 Drawing Figures Patented Jan. 7, 1975 3 Sheets-Sheet 1 Patented Jan. 7, 1975 3,858,511

5 Sheets-Sheet 2 FIG. 3

FIG.4

FIG. 5

5 Sheets-$heet 5 FIG.6

1 FLEXIBLE PLATE SADDLE LOCK-UP SYSTEM BACKGROUND OF THE INVENTION The present invention pertains to supports for attaching flexible printing plates onto the cylinder of a printing press. There as been an increased demand in the printing business for both high quality black and white and for color advertising in newspapers which is comparable with that found in magazines where etched or engraved printing plates are used. Conventional newspaper presses, however, presently employ lead stereotype printing plates which have known limitations as to quality of black and white and color printing caused by the inherent characteristics of the plates. Newspapers have been greatly interested in the use of photopolymer flexible plate systems due to their high quality of printing, moderate cost of equipment and materials, simplicity and reliability of plate making equipment and lack of pollution problems connected with metal engraving processes. A major problem with these systems has been the retention of the flexible plate on press. The present invention provides a reliable, easy 'to use saddle lock-up system which firmly grips the leading edge of a printing plate, tensions the plate for uniform printing quality and which allows the plate to be taken off press from either end of the saddle.

SUMMARY OF THE INVENTION It is a purpose of this invention to provide a saddle lock-up system that will firmly grip and tension a flexible printing plate. To accomplish'this purpose, the present invention provides in combination: a cam biased clamping bar on the leading edge of the saddle, a spring biased slotted bar on the trailing edge of said saddle, said slotted bar being moved to itsv nontensioning position by the use of a separate tool which interacts between the leading edge of one saddle and the trailing edge of another saddle when two or more saddles are mounted on press.

OBJECTS OF THE INVENTION It is a primary object of the instant invention to provide a saddle lock-up system that will facilitate quick and easy attachment and tensioning of a flexible printing plate on a printing cylinder.

It is a further object of the instant invention to provide a saddle lock-up system that will firmly grip and apply tension to a flexible printing plate.

A further object of the instant invention is to provide a flexible plate lock-up system that can be used for double truck style newspaper printing.

Still another object of the instant invention is to provide a saddle lock-up which can be operated at both the leading and trailing edges of the saddle for mounting and dismounting the plate.

DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a portion of the leading edge of a first saddle and the trailing edge of a second saddle in their relative positions when mounted on press.

FIG. 2 is a perspective view of the tool utilized in mounting flexible plates on the saddles shown in FIG. 1.

FIG. 3 is a section view taken along lines 33 in FIG. 1.

FIG. 4 is a section view taken along section lines 4-4 in FIG. 1.

FIG. 5 is a section view taken along section lines 5-5 in FIG. 1.

FIG. 6 is a section view taken along line 66 of FIG. 1.

FIG. 7 is a section view taken along section line 77 of FIG. 1.

FIG. 8 is a perspective view similar to that in FIG. 1 of an alternative embodiment utilizing a fixed slot in the leading edge of the saddle.

DESCRIPTION OF THE PREFERRED EMBODIMENT With continued reference to the drawing, the invention comprises means for locking flexible printing plates to a letterpress saddle and means for maintaining tension in the printing plate. As can be seen in FIG. 1 a known form of press cylinder construction comprises a plurality of arcuately formed saddles shown generally as 10 attached to a solid cylinder (not shown) by means of a system of internal claws or clamping bolts (not shown). The p'rintingcylinder commonly receives two saddles, each occupying one half of the cylinder. The flexible printing plate is not shown. It is important to be able to change the flexible printing plates that will be held by the saddles l0 quickly, because with modern high speed operation a large quantity of printing is run off ina short time, following which the plates must be changed, and if plate change cannot be done quickly,

the down time of the printing press will be excessive. The saddles 10 are preferably formed of a strong light metal such as magnesium or aluminum. Each saddle has a leading edge and a trailing edge as generally noted at 12 and 14, respectively, and is adapted to support a flexible printing plate (not shown). One end of a flexible printing plate is securely clamped in the groove 16 in the leading edge 12. The other end of said flexible plate would be secured at the respective trailing edge of the same saddle (not shown) in a groove identical to groove 18 of the trailing edge 14 that is shown.

The detailed construction of the leading edge 12 can be better seen in FIGS. 3-5. The flexible printing plate (not shown) is firmly gripped in groove 16 by clamping bar 20. Groove 16 is defined as the space between the clamping bar 20 and the curved base plate 22. Base plate 22 and clamping bar 20 both are machined with serrations 24 to firmly grip the flexible printing plate. Base plate 22 has been machined on its under side to provide a support area for securing member 26 which is attached to the base plate 22 by fastener 28. Member 26 could be secured to base plate 22 by any other equivalent fastening means such as by welding. Clamping bar 20 slides with respect to member 26 toward and away from base plate 22. In FIGS. 1 and 3 it can be seen that clamping bar 20 is provided with slots 30 to accommodate movement of the clamping bar 20 toward and away from base plate 22. Flat head bolts 32 maintain contact between the clamping bar 20 and member 26. It can be seen that the slots 30 are provided with internal shoulders 34 which interact with the bolts 32 to slidably secure the clamping bar 20 to the member 26.

Clamping bar 20 is moved toward base plate 22 by a cam member 36. Although only one cam member 36 is shown in FIG. 1, a second cam member (not shown) 3 is provided in a position that is symmetrical in the transverse'direction with respect to the pin 38. As can be seen in FIG. 4, cam member 36 comprises two cylindrical sections 40 and 42 that are axially offset with re spect to each other. Top section 40 is seated within a cylindrical bore 41 in clamping bar 20. Bottom section 42 is seated within a slot 43 in securing member 26. The smaller dimension of slot 43 can be seen in FIG. 4. The larger dimension (not shown) of slot 43 is parallel to the length of the clamping bar to permit rotational movement of the cam member 36. Cam member 36 is rotated by insertion and rotation of the tool 46 shown in FIG. 2. The screw driver like end 48 of the tool 46 is inserted in slot 44 and cam member 36 is rotated. Rotation of the cam member 36 moves the clamping bar 20 toward and away from base plate 22. Cam member 36' is conveniently retained in axial position by circular clip 47. As can be seen in FIG. 5, pin 38 is rigidly secured to support member 26 as shown at 48 by a weld or equivalent means. Pin 38 is used in connection with the trailing end 14, its purpose to be discussed later. It should be within the scope of the invention to replace unitary clamping bar 20 with more than one bar.

The trailing edge 14 of the saddle is shown in detail in FIGS. 6 and 7. The trailing edge of the saddle comprises a bar 50 having a groove 18 for retention of a flexible printing plate. Bar 50 is biased away from curved base plate 22 by resilient means 52. Bar 50 is strengthened with a reinforcing I rib 54 as shown in FIGS. 1, 6 and 7. As can be seen in FIG. 7,the reinforcing rib 54 is machined near each end with a slot 56. Base plate 22 is provided on its underside with retaining screws 58 which extend through slots 56 to accommodate movement of bar 50 toward and away from base plate 22'. Resilient means 52, shown as springs are retained in bored portions 60 and 62 of the bar 50 and the base plate 22, respectively. Pin 38 and tool 46 are 'used to move the bar 50 toward the base plate 22 of trailing edge 14. The tool 46 having opening 64 (shown in phantom) is placed on top of pin 38 and is rotated such that the camming surface 51 of the tool 46 contacts the outer surface 66 of the bar 50. Rotation of the tool 46 will cause the bar 50 to move toward the base plate 22' compressing the resilient means 52.

' Other tools could obviously be used to move bar 50.

For example, the pin 38 and tool 46 could be eliminated and a conventional spreader tool (not shown) could be inserted between the bar 50 and member 26 to move the bar 50 toward base plate 22. In operation, the bar 50 is moved toward base plate 22 and theflexible printing plate is inserted into the notch 18. The bar 50 is then allowed to move away from base plate 22' by the force of the resilient means 52 to tension the flexible printing plate. Thus itcan be seen'that one end of a flexible plate is first inserted and firmly secured into the leading edge 12 and then the other end of the flexible plate is inserted into the trailing edge 14 of the same saddle to apply tension to said plate.

It would be within the scope of the instant invention to use a fixed groove 68 as shown in FIG. 8 instead of the clamping bar of FIG. 1. The flexible printing plate would first be inserted in the groove 68 and then tensioned in the trailing edge 14 as discussed previously. The groove 68 and corresponding groove 18 permit lateral movement of a printing plate on press for the purpose of registration of the plate with respect to the page to be printed. This capability is unique to the instant design.

In view of the foregoing, it can be seen that the plate securing and tensioning mechanism facilitates quick mounting and tensioning of a flexible printing plate about the saddle. It is also obvious that a flexible plate is capable of being removed from the saddle from either edge of the saddle shown in FIGS. 1-7 after it has been used.

It is understood that the invention is not limited to the precise description given, but the changes are contemplated as readily fall within the spirit of the invena base plate having a contact surface on its forward edge, said base plate having an underlying forward projecting ledge continuingpast said forward edge; an axially transverse clamping bar slideably connected to the top of said ledge of said base plate at the leading edge thereof, said clamping bar and the contact surface of said base plate defining a groove therebetween for receiving one end of a flexible printing plate, said clamping bar having a radially extending cylindrical bore therethrough; and

a cam member comprising two cylindrical sections that are axially offset with respect to each other, one of said sections seated within. said cylindrical bore and the other section rotatably connected to said ledge of said base plate, rotation of said cam member moving said clamping bar toward said base plate to effect clamping of the printing plate. 

1. A printing saddle for mounting flexible printing plates comprising: a semi-cylindrical saddle adapted to be attached to a printing cylinder, said saddle having a leading edge and a trailing edge, said leading edge containing means to secure one end of a printing plate and said trailing edge containing means to secure and tension the other end of a printing plate, said leading edge further comprising: a base plate having a contact surface on its forward edge, said base plate having an underlying forward projecting ledge continuing past said forward edge; an axially transverse clamping bar slideably connected to the top of said ledge of said base plate at the leading edge thereof, said clamping bar and the contact surface of said base plate defining a groove therebetween for receiving one end of a flexible printing plate, said clamping bar having a radially extending cylindrical bore therethrough; and a cam member comprising two cylindrical sections that are axially offset with respect to each other, one of said sections seated within said cylindrical bore and the other section rotatably connected to said ledge of said base plate, rotation of said cam member moving said clamping bar toward said base plate to effect clamping of the printing plate. 